Science behind making a roti

Many readers would have had the pleasure of enjoying puffed Roti's. This is perhaps one of the best form of breads that can be eaten for a lifetime, multiple times in a day.

Our mothers have learnt the art of making Roti's, and they are expert in doing this activity - every single roti gets puffed to the right level. However, most if not none are aware of the science behind making the roti. Here is a simple yet scientific explanation of the Roti making technique.

Roti is made from atta dough (coarsely grounded wheat). The dough must have the right water content, neither less nor more (as I will explain later).

We make small portions of the dough and then roll them into circular shape. The baking process starts from here.

We put the roti on the Pan (Tava) and I will refer to the surface that was first put on the Pan as surface 1. The whole roti is a bit soft and we must be careful not to distort its contours by pressing hard on the surface. Once this surface is slightly cooked, we flip it over.

What then, is the best time to flip? This knowledge comes with experience, but scientifically you do this when the surface 1 is slightly cooked, but has not become impermeable to heat. The fact that we leave it half cooked helps the cooking later. In practice it happens when some dough has both dry and wet patches of similar size.

We now flip the surface 2 of the roti on the Pan and let it harden - making it impermeable to steam. This is characterized by having a few dark spots (slight burn) on this surface. A hard surface is also less permeable to heat.

We now have a roti that is hard on one surface (surface 2) and a soft surface that is slightly heat permeable (surface 1).

At this point we flip the roti on the fire, placing surface 1 on the fire.

This is when magic happens; How?

The fire heats the  dough in the roti. This is because the surface on fire (surface 1), is permeable to heat due to it's softness and this conducts heat into the internal dough of roti.

The water within dough inside the roti, heats up & evaporates; expanding in volume. The water vapour tries to escape, but fortunately for us, surface 2 on the top is impermeable to air/steam. This stops the water vapour to escape from the top surface! But what about the bottom surface, surface 1?

Surface 1 which is placed on the fire is soon cooked and has become hard. Now the water vapour cannot even escape from the lower surface and in this process, our roti gets bloated! The cook can then turn the roti over multiple times to give it the desired burn and crispiness.

In summary, a good roti is cooked from outside by the pan & fire; on inside by the steam. Even when it gets cold the two internal surfaces do not stick to each other - as all the 4 surfaces of the roti are well cooked (2 additional surfaces are the internal surfaces).

Coming back to the water content in the dough.

If the water is less, then less vapour gets generated and the roti will not bloat enough. This also happens if surface 1 is cooked too hard. Not enough heat gets into the internals of the roti!

If the water content is high, then the dough is loose and cannot hold well and is often punctured so some parts of the surface, specially surface 2 are not cooked, letting vapour escape. Also too much of vapour punctures weak spots, that makes roti less cooked from inside.

Personally, I have done the whole process just a couple of times in my life, though I have been pampered through out my life by excellent rotis. I consider myself close to a connoisseur of rotis, specially after I discovered the science behind this.

This explanation will not make you a great roti cook, but if you are a great cook (which I assume many readers will be) you will see the science behind this and if you are not, you can become observant to look for subtleties in roti making and improve your skills. Finally if you are just a consumer (like me), read on and give expert comments on the quality of rotis.

Hope you enjoy cooking, making and eating roti's with a new perspective.

Note: Permeable - one that allows something to pass through it, Impermeable - one that does not.